Understanding SIP Trunking and How It Works

The need for communication capabilities has expanded for all companies across the globe. If enterprises want to make full use of their IP-PBXs, thereby communicating not only over IP within their enterprises but also outside, SIP Trunking is necessary. A SIP Trunk is provided by an Internet telephony service provider and enables companies to connect to the traditional PSTN network.

SIP Trunking allows the traditional bundle of wires needed for the connections to be replaced via a SIP service provider on the Internet. Utilizing SIP can also offer great savings in terms of costs for companies, thus eliminating the need for local PSTN gateways and other costly technologies.

There are three necessary components that must be present in order to employ successful trunking. One is a PBX with a SIP enabled trunk side, an enterprise edge device designed to understand SIP and an Internet telephony or trunking service provider.

The PBX is, in most cases, is an IP-based PBX that communicates with all endpoints over IP, but it is very similar to a traditional digital or analog PBX. The only requirement is that an interface for SIP trunking be available.

The enterprise border element is connected via the PBX on the LAN. The edge component can either be a firewall with complete support for SIP or an edge device connected to the firewall, and which handles the traversal of the SIP traffic.

The ITSP provides connectivity to the PSTN via the Internet for communication with mobile and fixed phones. Again, trunking may be employed here to handle these types of communications and meet even more business needs than ever before.